An exposure apparatus that uses extreme ultraviolet (EUV) light as exposure light (refer to Japanese Laid-Open Patent Publication No. 11-312638) may be a commonly known example of an exposure apparatus that includes a reflective optical member. Such an exposure apparatus includes an illumination optical system including a pair of fly-eye mirrors (reflective optical member), which can function as an optical integrator.
Each fly-eye mirror includes a plurality of mirror blocks, arranged on the setting surface of a base. Each mirror block includes a plurality of mirror elements, which are adjacent to each other in at least one of two perpendicular directions (first and second directions) within the setting surface of the base (refer to US 2007/0273859 A1). Each mirror element has a mirror surface for reflecting incident exposure light. A reflective film is formed on the mirror surface of each mirror element in units of mirror blocks.
Each mirror block of the fly-eye mirror includes a plurality of mirror elements arranged adjacent to each other in at least one of the first and second directions. The mirror blocks are positioned relative to each other and set on the setting surface of the base.